WELLINGTON • Lego products are becoming increasingly violent as toymakers engage in an "arms race" to retain children's attention in the digital age, according to New Zealand researchers .

The Canterbury University team said child's play was becoming more brutal, with a higher proportion of weapons appearing among Lego's building blocks and war-like scenarios featured in kit sets.

"The Lego company's products are not as innocent as they used to be," lead researcher Christoph Bartneck said yesterday.

In a peer-reviewed study published by the United States-based online journal PLOS ONE, the researchers said Lego "showed significant exponential increases of violence over time".

While Denmark-based Lego has been making plastic building blocks since 1949, the study found its first weapons were issued in 1978 when a castle kit included swords, axes and lances. An analysis found weapons were now included in 30 per cent of Lego kits.

Dr Bartneck said the percentage was probably higher as the data included only small, single-brick weapons, not items such as the best-selling Star Wars' Death Star, which in itself is a giant planet-destroying ray blaster.

The research examined Lego catalogues from 1973 to last year and found scenarios depicted in kits had become more violent.

"Currently, around 40 per cent of all pages contain some type of violence - in particular, scenarios involving shooting and threatening behaviour have increased over the years," it found. "The atmosphere of the violent acts is predominantly perceived as exciting."

Lego has radically reinvented itself since it almost went bankrupt in 2003-2004 as electronic games threatened its future. It began selling themed kits linked to popular movie franchises such as Star Wars, Batman and Harry Potter. It also created light-hearted computer games and animation. The result has been 11 straight years of growth.

Lego spokesman Troy Taylor said the company's products promoted a range of play activities such as construction, fantasy and conflict.

"As with other play types, conflict play is a natural part of a child's development," he said.

Mr Taylor said the weapons were always used for a broader purpose, such as saving the world, and character was emphasised over firepower.

"We always try and use humour where possible as it helps to tone down the level of conflict."

AGENCE FRANCE-PRESSE